Bulletproof glass and other security measures can make schools safer, but there's no way to completely eliminate the risk of violence, architects testified Friday before a panel set up by Gov. Dannel P. Malloy after the Newtown school shootings.

HARTFORD, Conn. — Bulletproof glass and other security measures can make schools safer, but there's no way to completely eliminate the risk of violence, architects testified Friday before a panel set up by Gov. Dannel P. Malloy after the Newtown school shootings.

The architects told the Sandy Hook Advisory Commission that there are numerous safety actions, both inexpensive and costly, that school officials can take. They include further limiting access to buildings, removing sight-line obstructions outside schools, installing locks on classroom doors, allowing police to access surveillance cameras inside schools from computers in their cruisers and putting up reinforced glass.

Classrooms can even be configured to make it look like they're empty from hallway doors, the architects said.

"The reality is hazards can arise in any one of these locations," said Jim LaPosta, chief architectural officer for JCJ Architecture in Hartford, referring to places inside and outside schools. "There is really nothing we can do to guarantee a risk-free environment."

What security experts can do, LaPosta said, is to assess the safety of schools and recommend changes including ways to slow down attacks. LaPosta said a main question is how to improve security without making schools less welcoming and more intimidating to students and the community.

Showing a picture of a castle on a video screen, LaPosta asked, "How do we fortify our schools without creating fortresses out of them?"

Commission member Ezra Griffith, a psychiatrist and research scientist at Yale University, questioned the need to make wholesale changes in school security.

"It doesn't make a lot of sense to me, because it's not a frequent phenomenon," Griffith said about mass shootings.

He added that many schools and colleges declined to make major security changes after the killings at Columbine High School and Virginia Tech because of cost and other factors.

On Dec. 14, 20-year-old Newtown resident Adam Lanza killed 20 first-graders, six educators and himself at Sandy Hook Elementary School, after having shot his mother to death earlier in the day at their home. The motive remains unclear.

The shootings happened after the school's entrances were scheduled to be locked when the school day began. Police said Lanza entered the school by shooting out the front entrance's windows.

Architect Glenn Gollenberg of the S/L/A/M Collaborative in Glastonbury said there are different levels of glass reinforcement all the way up to bulletproofing. But installing reinforced glass in schools can be costly — starting at $3,000 to $4,000 per classroom — and communities need to decide how much they're willing to spend on security measures.

Gollenberg showed the commission a minute-long video of men trying to break reinforced glass with a sledgehammer. They eventually managed to put a hole in the glass.

The architects said one of their most important recommendations was for school officials to work closely with police on incident response plans. While firefighters often are familiar with the layout of schools from inspections and drills, police officers can be less knowledgeable and that can lead to confusion when responding to violence, they said.

That's why, LaPosta said, it would be helpful if officers could access interior surveillance cameras from outside schools so they could see what's going on inside and respond appropriately.

The architects shied away from recommending statewide security mandates, saying safety decisions are best left to cities and towns.

The advisory commission is supposed to give a list of recommendations on school security, mental health issues and gun violence prevention to Malloy by March 15.